Chapter6: Life SystemsEcosystem • network of relationships among plants, animals

and the non-living constituents in an environment

Interacting agents include:A. Inorganic materials

• soils and minerals in the earth, gas in the atmosphere and the sun’s energy

B. Producers• all green plants

C. Consumers

Three types of consumers:

A. Primary Group • herbivores• plant eaters

B. Secondary Group

• carnivores• animal or meat eaters

C. Tertiary Group• omnivores• eat both plants and animals

*A sub-group of consumers are Decomposers. • bacteria and fungi that live off decaying

organisms

FOOD CHAIN

• an

energy system • sun --> producer > 1st consumer –> 2nd consumer

–>3rd consumer

Ex: plant ---> mouse---> cat ---> owl

• a linear sequence representing the nutrition of various species from the simplest plant through to top carnivores

Ex: rose–> greenfly –>ladybug –> sparrow –> sparrow-hawk

FOOD WEB

• a series of interconnected and overlapping food chains in an ecosystem

What is the main difference between a food chain and a food web?

• fo

od web is more complicated with many more parts while a food chain is simple with as few as three or four agents

Energy flow in an ecosystem:

• energy leaves the system as heat• some energy is used to maintain the plants life• about 10 percent of the energy goes from one

level to the next level

Food Pyramid • diagram used to represent energy flow in food

chains and food webs• shows each trophic level as a horizontal bar• producers are located on the bottom• consumers are placed on top of each other in

terms of size• each bar is drawn in proportion to the mass of

organisms giving the triangle shape• smaller number of organisms at the top of the

pyramid because energy is lost between levels• about 10% of food energy is passed on between

levels of the food chain or the trophic levels in the pyramid.

• number of organisms steadily decreases from the bottom to top

BIOLOGICAL

AMPLIFICATION

• term used to describe the fact that higher trophic levels

• occurrence of toxins has always been common in our

• lower order organisms ingest poison and it may or may

• chemicals in pesticides and insecticides collect

• higher order organisms have to eat many lower order organisms to survive increasing the amount of toxicity at the top of the food chain

WORLD ECOSYSTEMS Climax Vegetation

• is the natural vegetation of an area• grew without the assistance or interference of humans• humans did not plant, fertilize or water the vegetation in any

way• ecosystems are defined by the type of climax vegetation that

grows in it

• the type of vegetation is largely determined by the climate

World Ecosystems

Ecosystem Climate Type Climatic Conditions ClimaxVegetation

%

Tundra PolarSubarctic

short summers /very cold long winterstemperatures always less than -10 C

light precipitation

moss 11%

Boreal Forest Temperate Cold warm summersmoderate precipitation

fir treeblack spruce

17%

Temperate Forest Temperate Mild warm to hot summersmoderate to heavy precipitation.

deciduous trees 8%

Temperate Grassland SteppeTemperate Cold

light precipitationwarm to hot temperatures in summer

cold winters

short grass 13%

Savanna Tropical Wet & DrySemi-Arid

high temperatures most of yearlight to moderate precipitation usually

during one season

tall grass 10%

Desert Desert high temperatures all yearvery light precipitation

plants with long roots 19%

Tropical Rain Forest Tropical Wet high temperatures all yearheavy precipitation most of the year

thick forest with canopy 13%

Mountain Varied cold because of higher elevation barren 9%

Comparison between latitude and altitude in ecosystems:

• low latitude to high latitude = low altitude to high altitude

• vegetation changes from largest and most numerous species to hardly any in the polar regions

• follows a special sequence of tropical rain forest, temperate forest, coniferous forest, low herbaceous tundra

Plant & Animal Adaptations & World Ecosystems

Animal Ecosystem Adaptation Result

polar bear tundra white coatability to store fat

camouflageinsulation

cactus desert thick waxy skinlong roots

stores water

no water losswithstands drought

camelpocket mouse

desert stores waterbroad flat hoofs

hooded eyes

good for walkingprotected from storms

howler monkey rain forest long limbsflexible tail

move in the tall trees

orchid tropical rain forest

long rootsneeds little soil

leaves to extract nutrients from bark

grow on large treeshang on their limbs

fir tree coniferous waxy needles for leavesshallow roots

does not lose leaves

can stand cold winters, can grow in poor soil

The Relationship of Ecosystems to Climate

Introduction of New Organisms• food webs are not isolated• new species are often introduced into

ecosystems by accident and by design • moose, shrews and coyotes are animals that are

not “native” to this province• when a new species is introduced the complete

balance of the food web may be upset and threaten the survival of certain species

Case #1: Moose (Alces alces)

StatusNative to Labrador.

Introduced to Gander Bay, NF in 1878 and to Howley, NF in 1904.Habitat Moose are found on the wooded hillsides of the rocky western mountain ranges, along the margins of ponds, lakes and rivers of the boreal forest, swamps, bogs and also on the northern tundra. They also can be found in

fresh water feeding.

RangeMoose extend from the Alaska boundary all across Canada to the eastern tip of Newfoundland.

FoodDuring the winter it feeds on twigs and shrubs - about (18 - 22 kg) (40 to 50 pounds) a day. In the summer moose eat many types of leaves of trees and shrubs such as birch and maple. They also feeds on water plants consuming a total of (22 - 27 kg) (50 to 60 lbs.) a day

Predators/ThreatsBlack and grizzly bears are the main predators. Wolves kill them in winter when the snow is deep to their advantage or on ponds and lakes where it is easy for the moose to slip and fall. Wolverines and cougars are also known to kill calves. On the Island of Newfoundland, moose is an important game animal, with approximately 22,000 being harvested yearly.

LifespanMoose can live 20 years or more in the wild.

AppearanceMales have palmate flat antlers with small prongs projecting. The front legs are longer than the back giving the moose a humped appearance. It has a short and stubby

hairy tail, short neck, long nose, and ears like a mule. Under the throat hangs a pendant of fur about a foot long called a bell. In color the moose is dark brown to reddish brown with greyish white legs.

Breeding BiologyMoose often take more than one mate, but the bull usually stays with a given cow during most of the breeding season which begins in mid September.

Average Weight/Measurements On average an adult moose stands (1.5 - 1.8 m)(5 to 6 feet) high. Males weigh (850 to 1180 lbs.)(385 - 534 kg) and females (600 to 800 lbs)(270 - 362 kg).

Notes: An important big game animal for meat and trophies. Moose can swim as fast as two men paddling a canoe

and run up to 56 km/h on land. In North America the moose is the largest member of

the deer family Four animals were introduced to Newfoundland

(Howley) in 1904 from New Brunswick. In 1930 Newfoundland had its first hunting season for

moose.

Case #2: THE MASKED SHREW

• tiny animal was brought to Newfoundland in

1958 • served as a check on a forest pest called the larch sawfly• one year after the original 22 shrews were released over

130 shrews were recaptured • since its introduction this fast-spreading insect eater has

traveled across the Island and is found everywhere• has a great appetite sometimes eating its own weight or

more a day• heart can beat over 800 times per minute• hawks and owls enjoy eating shrews• often found in the stomachs of large trout and salmon• has a short lifespan of less than two years• has up to eleven young per litter several times a year

• can starve to death if not fed every 3-4 hours• nap but do not have long periods of sleep• smallest mammal weighs less than 6 grams• identifiable by its pronounced snout and small size

SOILSurface of the earth’s crust that is made up of:

a. inorganic material (mineral)b. organic material (living)c. waterd. air

Soil develops over time into a SOIL PROFILE depending on the climate and vegetation factors

SOIL LAYERS ARE AS FOLLOWS:

Zone O: Litter Layer• dark colour• rich in humus (dead leaves, grass clippings and

other matter)

Zone A: Topsoil Layer• minerals from Zone O deposited here

Zone B: Subsoil Layer• weathered parent material

Zone C: Bedrock• not an actual soil layer• made of rock• supports the soil layers above it

THREE PROCESSES INVOLVED IN SOIL FORMATION:

Process #1: LEACHING• the movement of water down the soil profile

• matter like humus moves to lower horizons• results in poor soil• occurs in areas with high mm

Process #2: ELUVIATION• downward movement in suspension of clay and other

fine materials• results in a coarse poor soil• occurs in areas with high mm

P Process #3: CAPILLARY ACTION• moisture and attracted soil particles rise up through

soils • water is drawn to the surface like a sponge• water evaporates leaving behind minerals like

calcium, potassium and phosphorus• soil is rich in minerals and fertility• occurs in areas with low mm

Soil Texture

Most soils are mixtures that fall between these extremes:

a. Sandy Soil• 85% sand

• loose and coarse• easily drains water• doesn’t promote plant growth

b. Clay Soil• 40% clay• has aluminum and water in it...allows it to bond• holds water like a sponge• restricts air flow• has little nitrogen...slow to warm, drain

c. Silty Soils• combine characteristics of sandy and clay soils

d. Loam• equal amounts of sand, silt and clay• great for farming

Soil Texture Graph

SOIL LOSS PATTERNS

a. Erosion• basic problem where water run-off occurs in sloped areas• valuable soil is washed away or blown away in dry

regions• results in 11 million hectares (ha) of farmland lost every

year

b. Poor Farming Practises • overgrazing by animals • repeated cropping• mechanical fertilizers and pesticides are making soil

sterile

c. Poor Water Management• irrigated crop land is waterlogged or salt levels build up

and poison the soil

d. Urbanization• building over valuable farm land

e. Deforestation • major problem in the tropical rain forests of the world -

soils exposed.• flooding with changes in the world’s climate patterns• tropical rain forests of South America or Amazon and

Africa with active deforestation are degrading the soils as they are exposed to the elements

• heavily leached by the rains with no forest and quickly lose their fertility

f. Desertification• loss of land into arid and semi-arid states through

careless land use • can lead to unproductive desert soil• Asia and Africa have the highest levels of soil loss

Ecosystem Change by Humans• in the short term, ecosystems are changed by human

activity• in the long term, huge areas of the earth have been

changed with tree removal and farming practises• problem areas of damage and risk on the map

Draining Wetlands• areas are drained for more residential, farming or

industrial land use• as a result water fowl and animals are removed from

the ecosystems

Desertification• spreading of deserts beyond their present borders• overgrazing and expanding farming into dryland areas

make deserts expand

Acid Rain• found in industrial nations

• comes from the burning of fossil fuels and the heavy use of automobiles as well as industrial pollution

• transported by wind and pollutes watersheds, kills plants, and kills water creatures

• kills fish and stunts treesDeforestation

• aggressive cutting practise of the earth’s forests by large companies

• especially destructive in the Amazon rain forest as well as boreal forest

SOLUTIONS • raise public awareness and governments must act

like watch dogs over the environment• need for a balance of economic development and

environment concerns

Wetlands:• restoration plan to replace areas already destroyed or

degraded

• do not fill in wet lands for housing, rather, use it as a part of housing development (parks and open space)

• allow continuous flow from any dams to keep rivers alive

Deforestation: • stricter cutting regulations by government• compulsory and monitored reforestation

program

Acid Rain:• stricter emission controls by government• recovery program for the endangered

ecosystems

Desertification:• wiser use or protection of areas close to

deserts• replanting program to get the vegetation

restored